I’m sorry you’ve had a bad interaction, and I hope you get everything straightened out.
Don’t give your phone number to strangers. Period. You can search for the profile picture in Google image search — most likely it’s “borrowed”.
I’d also avoid interaction with users who don’t have a track-record on italki, you know, public comments on discussions, notebook entries, notebook corrections, paid lessons, or at least a short introduction. A lack of posts can be a signal they’re not serious, if not necessarily a scammer. If they do have posts (or at least an introduction), feel free to send me the details and I’ll tell you if they’re really a native English speaker and whether or not they’re culturally Anglophone.
Always report scammers to italki immediately.